A year of work-group sessions, drafts, redrafts and heated debate on regulating development along the Mississippi River may have been for naught.

The Minnesota Department of Natural Resources, ordered by the Legislature to establish new rules for a 72-mile stretch of the river, missed a key deadline, meaning its authority to make the rules has expired.

Restarting the process would require the Legislature to grant the DNR more time, which some say is highly unlikely. Moreover, legislation was introduced last week to eliminate the rulemaking process altogether.

The area in question, the Mississippi River Corridor Critical Area (MRCCA), stretches from the Anoka County city of Ramsey to southeastern Dakota County. The rules, intended to standardize what is now a mishmash of local regulations, would dictate how tall buildings can be in the corridor and how near to the top of a bluff a structure could be built, for instance.

"It was disappointing to us, surely, that we weren't able to get updated, common-sense rules passed by the deadline," said Whitney Clark, executive director of Friends of the Mississippi River, an advocacy group deeply involved in the rulemaking.

Clark said his organization had little warning that the DNR would miss its deadline, which was 18 months after the effective date of the law establishing the rulemaking process.

The agency missed the deadline because it lacked enough time to evaluate public input, said DNR hydrologist Jeff Berg, who helps head the rulemaking project.

Berg said 18 months wasn't a realistic time frame to get all differences settled.

"There's a pretty large gap in opinions," he said.

The 2009 Legislature instructed the DNR to create the guidelines and appropriated $250,000 for the task in 2010 and again in 2011.

Two DNR staff members led the project, and others worked on it as well. They met with the staffs and officials from all 30 cities and townships inside the corridor, convened meetings and two open houses, created three drafts of the standards, and met with interest groups to get their comments.

But some municipalities and lobbying groups complained that the DNR was overstepping its boundaries and not adequately balancing environmental protections and other local interests.

Jan. 1 was the deadline for the DNR to publish notice of its intent to adopt the rules. Under state statute, since notice was not given in time, the authority for the rules expired.

What happens next depends on the Legislature. It could do nothing, which would terminate the rulemaking process; repeal the legislation that directed the process, or authorize the DNR to continue.

Help from the Capitol seems unlikely with Republicans in charge of the Legislature, Clark said.

"If we could just go to the Legislature and the DNR could just get more time, we would be in support of this," he said. "I don't think there's a chance of that happening."

Sen. Benjamin Kruse, R-Brooklyn Park, who introduced the bill to terminate the process, said that the rules would have been detrimental to residents.

Residents "are kind of out in limbo right now. ... What we want to do is get that cleared up for them," Kruse said.

To Berg's knowledge, DNR management has not decided how to proceed, he said. The agency is working on a new draft of the rules that it hopes to complete this week.

Even if the rules aren't enacted, Berg said, the year was not a waste.

"If the executive branch or the Legislature decides to take this up again, at least we will have a starting point."